I hang all my steel with old rubber belting. You can get ot from implement places that repair big round hay bailers like Vermeer or JD. The belting will take hits for years and stil hold the steel.
AR 500 is worth every penny. It lasts and rings much better than mild steel.
Add to your terraces or push up enough dirt so you have a decent sized back stop behind th target. This will help you spot misses to get dialed in. Also if your dirt is rich soil or moist spread a bag of ag-lime behind the target and mix it in. This will make your bullet splashes more visable as it will send off a better dust ball.
Lastly, replace your rangefinder with a better model that has a smaller beam divergence. That way you will know if that last terrace is at 1320 or 1330 yards.